1. Strategies and agents
in supragingival
in chemical plaque control
MICHEL BRECX
Periodontology 2000, Vol. 15
5조 1번 고상훈

2. Mechanisms of supragingival
dental plaque formation
• Early human dental plaque formation is
initiated by the deposition of a thin biofilm
mainly derived from salivary glycoproteins
onto the tooth surface
• Plaque formation cannot be stopped, but
its accumulation does not cause any harm
if the surface coating on the teeth is
devoid of bacteria

3. Mechanisms of supragingival
dental plaque formation
• When one or two layers of bacteria are
present on the tooth surface in a healthy
individual, the subject’s immune system
can cope with these microorganisms, and
the subject can thus present a healthy
gingiva
• Therefore, disturbing plaque accumulation
is of major importance

4. Mechanisms of supragingival
dental plaque formation

5. Chemical plaque control
• The present meaning of dental plaque
control includes only the supragingival and
marginal areas because mouthwashes
used under normal conditions do not reach
the subgingival area
• The most tested and effective antiplaque
agent known today is chlorhexidine

6. Chemical plaque control
• The mode of action of chlorhexidine against bacteria is
well understood and is concentration dependent.
• Chlorhexidine acts on the cell wall of the
microorganisms by changing their surface structures.
Osmotic equilibrium is lost and, as a consequence,
cytoplasmic membrane is extruded, vesicles are
formed and the cytoplasm precipitates
• Because chlorhexidine has been shown to be able to
break up existing dental plaque, it can really be
considered as a potent antibacterial agent, bactericidal
at high concentration and bacteriostatic at lower
concentration, such as when gradually diluted in saliva
over time.

7. Chemical plaque control
• Many substances have some degree of
antimicrobial efficacy, especially in vitro, but it
is totally impractical to ask everybody to rinse
his or her mouth ten times a day, because the
solution is completely devoid of substantivity,
and rapidly diluted by and swallowed with
saliva.
• The agents that do not exhibit any significant
substantivity (only minutes) were categorized
as first-generation antimicrobial agents.

8. Chemical plaque control
• Second-generation antimicrobial agents are
characterized by high substantivity, that is,
retention of 25-30% after each 1-minute
mouthrinse. Such compounds remain active
in situ for hours
• Substances with mild antibacterial effect but
that interfere with bacterial adhesion are
referred to as third-generation antimicrobial
agents
• A fourth generation could be envisaged

9. Chemical plaque control

10. Strategies for dental plaque control
• When a mouthwash can reduce plaque
development by keeping down the numbers of
viable bacteria, chemotherapeutic as well as
salivary compounds may act synergistically.
• Therefore, the combination of mechanical and
chemical oral hygiene offers the greatest efficacy,
because the bulk of plaque is reduced
mechanically, leaving behind only disorganized
and thin dental plaque that can easily be further
reduced by chemical means.

11. Strategies for dental plaque control